isBusinessEmail

isBusinessEmail provides a free API to determine whether an email address or domain belongs to a business, detecting Google Workspace and Microsoft 365 usage. The service offers up to 100 free checks per day, stores no email data, and is EU‑hosted, making it suitable for privacy‑focused applications. Users can obtain an API key instantly without a credit card, and the platform includes tools, lists, and integrations for developers.

isBusinessEmail publishes 4 API contracts indexed on the APIs.io network, including Check API, Feedback API, Health API, and 1 more. Tagged areas include Company, EmailVerification, BusinessTools, API, and EUHosted.

The isBusinessEmail catalog on APIs.io includes 1 JSON-LD context and 1 Spectral governance ruleset.

isBusinessEmail’s developer surface includes changelog, authentication, documentation, API reference, getting-started guide, support, engineering blog, and 23 more developer resources.

🌐 Visit website 📡 Source on GitHub
57.0/100 strong Agent 47/100 agent ready Full breakdown ↓
scored 2026-10-09 · rubric v0.23.0
1 published contract
CompanyEmailVerificationBusinessToolsAPIEUHosted

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-10-09 · rubric v0.23.0
Composite quality — 57.0/100 · strong
Contract Quality 11.3 / 21
Developer Ergonomics 8.1 / 17
Access Clarity 5.8 / 17
Operational Transparency 7.6 / 11
Contract Governance 8.1 / 10
Discoverability 5.6 / 9
Regulatory Posture 4.6 / 15
Agent readiness — 47/100 · agent ready
Machine-Readable Contract 18 / 18
Agentic Access Contract 10 / 10
Documented Reversibility 0 / 6
MCP Server 12 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 8 / 8
Request/Response Examples 7 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 0 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Delegated User Identity 6 / 6
Protected Resource Metadata 5 / 5
Registration Without a Human 6 / 6
Agentic Commerce Well-Known Document 0 / 5
Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.
Create-or-Update Ergonomics could not be measured. We hold no machine-readable contract for this provider to read, so there is nothing to measure a write surface against. Excluded rather than scored zero: never-measured and measured-empty are different facts. Publishing an OpenAPI is what makes this facet — and several others — scorable at all.
The six quality facets above are damped to 85 points between them, because the conditional facet above carries the other 15. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 85% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/isbusinessemail: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 4

Individual APIs this provider publishes, each with its own machine-readable definition.

isBusinessEmail Check API

The Check API from isBusinessEmail — 2 operation(s) for check.

isBusinessEmail Feedback API

The Feedback API from isBusinessEmail — 1 operation(s) for feedback.

isBusinessEmail Health API

The Health API from isBusinessEmail — 1 operation(s) for health.

isBusinessEmail Usage API

The Usage API from isBusinessEmail — 1 operation(s) for usage.

Rate Limits 1

Documented rate limits and quota policies.

Isbusinessemail Rate Limits

2 limits

RATE LIMITS

Semantic Vocabularies 1

JSON-LD contexts and semantic vocabularies used across these APIs.

Isbusinessemail Context

2 classes · 35 properties

JSON-LD

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

isBusinessEmail API Rules

13 rules · 10 errors 1 warnings 2 info

SPECTRAL

JSON Schema 1

Standalone JSON Schema definitions for this provider's data models.

CheckResult

29 properties

JSON SCHEMA

Security Posture 3

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Isbusinessemail Authentication

apiKey/http · 2 schemes

SECURITY

Isbusinessemail Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Isbusinessemail Vulnerability Disclosure

security.txt · contact published

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Isbusinessemail Agentic Access

6 operations · 3 acting

6 operations · 3 acting

AGENTIC

Resources

Get Started 2

Portal, sign-up, and the first successful call

Login
Login
 GettingStarted
GettingStarted

Documentation 2

Reference material describing how the API behaves

Documentation
Documentation
 APIReference
APIReference

Agent Surfaces 3

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess
AgenticAccess
 LLMsTxt
LLMsTxt
 WellKnown
WellKnown

Design & Contract 7

Pagination, idempotency, versioning, errors, and events

Spectral
Spectral
 JSONLD
JSONLD
 Vocabulary
Vocabulary
 DataModel
DataModel
 Lifecycle
Lifecycle
 ErrorCatalog
ErrorCatalog
 Conformance
Conformance

Scroll for all 7

Access & Security 5

Authentication, authorization, and security posture

SecurityTxt
SecurityTxt
 Security
Security
 Authentication
Authentication
 VulnerabilityDisclosure
VulnerabilityDisclosure
 DomainSecurity
DomainSecurity

Operate 5

Status, limits, changes, and where to get help

RateLimits
RateLimits
 Deprecation
Deprecation
 StatusPage
StatusPage
 ChangeLog
ChangeLog
 Support
Support

Commercial 2

Pricing, plans, and the legal terms of use

TermsOfService
TermsOfService
 PrivacyPolicy
PrivacyPolicy

Company 2

The organization behind the API

Website
Website
 Blog
Blog

Other 2

Properties that don't map to a standard resource type

Hosts
Hosts
 Vendors
Vendors

Source (apis.yml)

apis.yml Raw ↑ 
aid: isbusinessemail
name: isBusinessEmail
image: https://isbusinessemail.com/og/default.png
description: isBusinessEmail provides a free API to determine whether an email address or domain belongs to a business, detecting
  Google Workspace and Microsoft 365 usage. The service offers up to 100 free checks per day, stores no email data, and is
  EU‑hosted, making it suitable for privacy‑focused applications. Users can obtain an API key instantly without a credit card,
  and the platform includes tools, lists, and integrations for developers.
url: https://raw.githubusercontent.com/api-evangelist/isbusinessemail/refs/heads/main/apis.yml
x-type: company
x-source: harvest:new-submission
x-tier: profiled
x-tier-reason: enrichment pass 2026-10-05 (modular-v1; was harvest)
specificationVersion: '0.20'
created: '2026-10-05'
modified: '2026-10-05'
tags:
- Company
- EmailVerification
- BusinessTools
- API
- EUHosted
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com
- FN: APIs.json
  email: info@apis.io
common:
- type: AgenticAccess
  url: agentic-access/isbusinessemail-agentic-access.yml
- type: RateLimits
  url: rate-limits/isbusinessemail-rate-limits.yml
- type: Spectral
  url: rules/isbusinessemail-rules.yml
- type: JSONLD
  url: json-ld/isbusinessemail-context.jsonld
- type: Vocabulary
  url: vocabulary/isbusinessemail-vocabulary.yml
- type: DataModel
  url: data-model/isbusinessemail-data-model.yml
- type: Deprecation
  url: lifecycle/isbusinessemail-lifecycle.yml
- type: Lifecycle
  url: lifecycle/isbusinessemail-lifecycle.yml
- type: ErrorCatalog
  url: errors/isbusinessemail-problem-types.yml
- type: Conformance
  url: conformance/isbusinessemail-conformance.yml
- type: LLMsTxt
  url: llms/isbusinessemail-llms.txt
- type: SecurityTxt
  url: well-known/isbusinessemail-security.txt
- type: WellKnown
  url: well-known/isbusinessemail-well-known.yml
- type: Hosts
  url: hosts/isbusinessemail-hosts.yml
- type: Vendors
  url: vendors/isbusinessemail-vendors.yml
- type: StatusPage
  url: https://status.isbusinessemail.com
- type: Security
  url: https://isbusinessemail.com/security
- type: Login
  url: https://isbusinessemail.com/login
- type: ChangeLog
  url: https://isbusinessemail.com/changelog
- type: Authentication
  url: authentication/isbusinessemail-authentication.yml
- type: VulnerabilityDisclosure
  url: security/isbusinessemail-vulnerability-disclosure.yml
- type: DomainSecurity
  url: security/isbusinessemail-domain-security.yml
- type: Website
  url: https://isbusinessemail.com
- type: Documentation
  url: https://isbusinessemail.com/docs
- type: APIReference
  url: https://isbusinessemail.com/docs/api
- type: GettingStarted
  url: https://isbusinessemail.com/docs/quickstart
- type: Support
  url: https://isbusinessemail.com/contact
- type: Blog
  url: https://isbusinessemail.com/blog
- type: TermsOfService
  url: https://isbusinessemail.com/terms
- type: PrivacyPolicy
  url: https://isbusinessemail.com/privacy
apis:
- aid: isbusinessemail:isbusinessemail-check-api
  name: isBusinessEmail Check API
  description: The Check API from isBusinessEmail — 2 operation(s) for check.
  humanURL: https://isbusinessemail.com/docs/api
  baseURL: https://api.isbusinessemail.com
  tags:
  - Check
  properties:
  - type: OpenAPI
    url: openapi/isbusinessemail-check-api-openapi.yml
  - type: JSONSchema
    url: json-schema/isbusinessemail-check-result-schema.json
- aid: isbusinessemail:isbusinessemail-feedback-api
  name: isBusinessEmail Feedback API
  description: The Feedback API from isBusinessEmail — 1 operation(s) for feedback.
  humanURL: https://isbusinessemail.com/docs/api
  baseURL: https://api.isbusinessemail.com
  tags:
  - Feedback
  properties:
  - type: OpenAPI
    url: openapi/isbusinessemail-feedback-api-openapi.yml
  - type: JSONSchema
    url: json-schema/isbusinessemail-check-result-schema.json
- aid: isbusinessemail:isbusinessemail-health-api
  name: isBusinessEmail Health API
  description: The Health API from isBusinessEmail — 1 operation(s) for health.
  humanURL: https://isbusinessemail.com/docs/api
  baseURL: https://api.isbusinessemail.com
  tags:
  - Health
  properties:
  - type: OpenAPI
    url: openapi/isbusinessemail-health-api-openapi.yml
  - type: JSONSchema
    url: json-schema/isbusinessemail-check-result-schema.json
- aid: isbusinessemail:isbusinessemail-usage-api
  name: isBusinessEmail Usage API
  description: The Usage API from isBusinessEmail — 1 operation(s) for usage.
  humanURL: https://isbusinessemail.com/docs/api
  baseURL: https://api.isbusinessemail.com
  tags:
  - Usage
  properties:
  - type: OpenAPI
    url: openapi/isbusinessemail-usage-api-openapi.yml
  - type: JSONSchema
    url: json-schema/isbusinessemail-check-result-schema.json
x-submission-notes: Tilfortis MB (Lithuania).
x-submission-probe: api.isbusinessemail.com 200 JSON index; /openapi.json 200 (OAS 3.1); /mcp POST 401 'Connect with OAuth
  or send API key'; invented path 404 problem+json; /docs and llms.txt 200.
x-submitted-by: hello@isbusinessemail.com (apis.io/add, 2026-10-05T07:56:41.786Z)
x-coverage:
  state: gated
  reason: partner-login
  method: derived
  generated: '2026-10-05'
  generator: derive-coverage.py (pre-flight evidence)
  detail: the company serves an API surface but requires credentials before any description of it can be read
  evidence:
  - url: https://api.isbusinessemail.com/openapi.json
    status: null
  - url: https://api.isbusinessemail.com/mcp
    status: 401
  - url: https://isbusinessemail.com
    status: 200
x-enrichment:
  date: '2026-10-05'
  status: enriched
  artifacts_added: 22
  pass: modular-v1
  engine: identity=local,contract=local,surfaces=local,docs=local,regulatory=local

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